1. Field
Apparatuses and methods consistent with exemplary embodiments relate to analyzing body component by using an optical measuring device.
2. Description of Related Art
An optical measurement method using infrared light or near infrared ray (NIR) may be used to measure a certain body component, such as blood sugar. By using the optical measurement method, a component in an object may be detected and/or analyzed in a non-invasive manner, or a diagnosis can be performed through the detection and/or the analysis. The optical measurement method includes a spectrum analysis method of detecting and/or analyzing a specific component by analyzing light absorptivity in a particular wavelength of transmitted light or reflected light spectrum, and the main example is a spectroscopic analysis method using a fourier transform infrared spectrometer (FTIR) large-scale spectroscopy.
In the spectrum analysis method, when measuring light emitted from a light source, for example a near infrared ray, is reflected from an object to be measured, and the reflected light is detected and analyzed. The reflected light includes light reflected from a surface as well as light passing through the object by a predetermined distance and reflected from the object. In the latter case, a predetermined distance that the measuring light passes through the object refers to an optical path length. Since the reflected light includes information on a component in the object when the measuring light passes through the object by an optical path length, the reflected light should have less noise to get accurate information, and the measuring light should sufficiently pass through the object by the optical length required for a measurement purpose. However, when the optical path length is excessively long, the intensity of the reflected light that a light detecting unit receives becomes weak, and a spectrum signal may be reduced, and thus it is preferable that the optical path length be stably maintained to suit a measurement purpose and/or a kind of component to be measured.
To this end, an optical measuring device capable of providing various optical path lengths is proposed. For example, a fiber probe including multiple light emitters or multiple light detectors may be used. The optical path length of the fiber probe can be adjusted by varying a distance between the light detector and the light emitter used for actual measurement.
Measurement of biometric information may be performed by a portable electronic device, such as a smart phone, or a wearable electronic device, such as a smart band, a smart watch and a smart glass. It is being concerned that the above-described optical measuring device is mounted to an electronic device as one of bio-related functions. Users can conveniently measure or analyze a subcutaneous component, such as a blood sugar, using the optical measuring device mounted on an electronic device regardless of time and place.
However, when the portable electronic device or wearable electronic device mounted with the optical measuring device is used, an interfacing status with the object (e.g., a skin) may vary depending on a user, and the interfacing status may also vary depending on a circumstance of the measurement (e.g., the position of skin in contact with the electronic device, a contact angle, contact tightness, and the like) even if the user is the same. For example, the position at which a smart watch is worn and the contact tightness between the smart watch and a skin generally vary depending on use every time a user wears the smart watch. Even if the smart watch is worn, an interfacing status between the smart watch and the skin may vary depending on time.
Therefore, when the optical measuring device is mounted on the portable electronic device or the wearable electronic device, it is important to ensure an optical path length to be a target beam path length according with a measurement purpose or a component and to uniformly maintain the optical path length every measurement.